U.S. patent number 10,094,377 [Application Number 14/362,203] was granted by the patent office on 2018-10-09 for oil pump for vehicle and vehicle with the same.
This patent grant is currently assigned to AISIN AW CO., LTD., TOYOTA JIDOSHA KABUSHIKI KAISHA. The grantee listed for this patent is Tomoo Atarashi, Hiromichi Kimura, Katsuhide Kitagawa, Takeshi Kuwahara, Kunio Morisawa, Tatsuo Obata, Masamitsu Seno, Hirotaka Yata. Invention is credited to Tomoo Atarashi, Hiromichi Kimura, Katsuhide Kitagawa, Takeshi Kuwahara, Kunio Morisawa, Tatsuo Obata, Masamitsu Seno, Hirotaka Yata.
United States Patent |
10,094,377 |
Obata , et al. |
October 9, 2018 |
Oil pump for vehicle and vehicle with the same
Abstract
An oil pump for a vehicle includes a driven gear, a drive gear,
a pump body, and a plate. The drive gear engages the driven gear.
The pump body is secured to a rear cover of a transaxle case. The
plate is interposed between the rear cover and the pump body. A
pump chamber is formed between the rear cover and the pump body.
The driven gear and the drive gear are housed in the pump chamber.
The pump chamber is formed: between the plate and the pump body, or
between the plate and the rear cover.
Inventors: |
Obata; Tatsuo (Toyota,
JP), Kimura; Hiromichi (Okazaki, JP),
Kuwahara; Takeshi (Nisshin, JP), Kitagawa;
Katsuhide (Seto, JP), Morisawa; Kunio (Toyota,
JP), Seno; Masamitsu (Anjo, JP), Yata;
Hirotaka (Kariya, JP), Atarashi; Tomoo (Kariya,
JP) |
Applicant: |
Name |
City |
State |
Country |
Type |
Obata; Tatsuo
Kimura; Hiromichi
Kuwahara; Takeshi
Kitagawa; Katsuhide
Morisawa; Kunio
Seno; Masamitsu
Yata; Hirotaka
Atarashi; Tomoo |
Toyota
Okazaki
Nisshin
Seto
Toyota
Anjo
Kariya
Kariya |
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A |
JP
JP
JP
JP
JP
JP
JP
JP |
|
|
Assignee: |
TOYOTA JIDOSHA KABUSHIKI KAISHA
(Toyota-shi, Aichi-ken, JP)
AISIN AW CO., LTD. (Anjo-shi, Aichi-ken, JP)
|
Family
ID: |
47561671 |
Appl.
No.: |
14/362,203 |
Filed: |
November 29, 2012 |
PCT
Filed: |
November 29, 2012 |
PCT No.: |
PCT/IB2012/002534 |
371(c)(1),(2),(4) Date: |
June 02, 2014 |
PCT
Pub. No.: |
WO2013/084039 |
PCT
Pub. Date: |
June 13, 2013 |
Prior Publication Data
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|
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Document
Identifier |
Publication Date |
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US 20140341757 A1 |
Nov 20, 2014 |
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Foreign Application Priority Data
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Dec 5, 2011 [JP] |
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2011-266236 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F04C
2/00 (20130101); F16H 57/0476 (20130101); B60K
6/405 (20130101); F04C 14/24 (20130101); F04C
14/26 (20130101); B60K 17/12 (20130101); F04C
2/102 (20130101); F04C 2210/206 (20130101); F16H
57/0486 (20130101); F04C 2/086 (20130101) |
Current International
Class: |
F04C
2/00 (20060101); F16H 57/04 (20100101); B60K
17/12 (20060101); B60K 6/405 (20071001); F04C
14/26 (20060101); F04C 28/24 (20060101); F04C
14/24 (20060101); F04C 2/08 (20060101); F04C
2/10 (20060101) |
Field of
Search: |
;417/310 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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102235352 |
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Nov 2011 |
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CN |
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3638848 |
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May 1988 |
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DE |
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2002-070753 |
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Mar 2002 |
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JP |
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2011-174583 |
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Sep 2011 |
|
JP |
|
Primary Examiner: Kramer; Devon
Assistant Examiner: Cash; Thomas
Attorney, Agent or Firm: Sughrue Mion, PLLC
Claims
The invention claimed is:
1. An oil pump for a vehicle, comprising: a driven gear; a drive
gear that engages the driven gear; a pump body secured to a rear
cover of a transaxle case; a plate interposed between the rear
cover and the pump body, wherein the pump body is disposed at a
first side of the plate, and the rear cover is disposed at a second
side of the plate that is opposite to the first side of the plate;
a pump chamber formed between the plate and the pump body, wherein
the driven gear and the drive gear are housed in the pump chamber,
and an oil passage between the rear cover and the pump second side
of the plate; and a relief valve comprising a valve element, a
valve chamber, and a spring, wherein: the valve chamber houses the
valve element and is formed between the first side of the plate and
the pump body; the spring is housed in the valve chamber and biases
the valve element in a valve closing direction; the plate includes
a through hole extending from the valve chamber to the oil passage,
the through hole being closed by seating of the valve element on
the first side of the plate, and the valve element covering the
through hole; and the oil passage communicates with an oil passage
formed in the pump body when the relief valve opens.
2. The oil pump according to claim 1, wherein the plate is made of
metal, the metal having a higher strength than strengths of the
rear cover and the pump body.
3. The oil pump according to claim 2, wherein: the rear cover and
the pump body are made of light metal; and the plate is made of a
steel plate.
4. The oil pump according to claim 1, wherein the rear cover is
supported by a mounting unit, the mounting unit being disposed in a
vehicle body.
5. The oil pump according to claim 1, wherein: the transaxle case
houses an electric motor; and the pump body rotatably supports a
rotor of the electric motor via a bearing.
6. The oil pump according to claim 1, wherein: the plate includes a
plurality of the through holes; a plurality of the relief valves is
provided at the first side of the plate; and the relief valves are
disposed corresponding to the plurality of the through holes and
have mutually different valve characteristics.
7. The oil pump according to claim 6, wherein: respective valve
elements of the plurality of the relief valves are made of a same
component; respective springs of the plurality of the relief valves
are made of a same component; and the through holes have mutually
different diameters.
8. The oil pump according to claim 1, wherein: the plate, the
relief valve, and the pump body constitute a module as a unit; and
the module is mounted on the rear cover.
9. A vehicle comprising: a rear cover of a transaxle case; an oil
pump comprising a driven gear, a drive gear, a pump body, and a
plate, wherein the plate has a first side and a second side that is
opposite to the first side; an oil passage between the rear cover
and the second side of the plate; and a relief valve comprising a
valve element, a valve chamber, and a spring, wherein: the valve
chamber houses the valve element and is formed between the first
side of the plate and the pump body; the spring is housed in the
valve chamber and biases the valve element in a valve closing
direction; the plate includes a through hole extending from the
valve chamber to the oil passage, the through hole being closed by
seating of the valve element on the first side of the plate and the
valve element covering the through hole; the drive gear engages the
driven gear; the pump body is secured to the rear cover; a pump
chamber is formed between the plate and the pump body; the driven
gear and the drive gear are housed in the pump chamber; and the
plate is interposed between the rear cover and the pump body.
10. The vehicle according to claim 9 further comprising a mounting
unit that is disposed in a vehicle body of the vehicle and supports
the rear cover.
11. The vehicle according to claim 4 further comprising: an
electric motor housed in the transaxle case; and a bearing, wherein
the pump body rotatably supports a rotor of the electric motor via
the bearing.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to an oil pump for a vehicle with a pump
body that is secured to a rear cover of a transaxle case and a
vehicle with the oil pump.
2. Description of Related Art
As disclosed in Japanese Patent Application Publication No.
2002-70753 (JP 2002-70753 A), the oil pump for a vehicle is
disposed, for example, at an input side of a transaxle. The oil
pump for a vehicle disclosed in JP 2002-70753 A includes a driven
gear, a drive gear that engages the driven gear, and a pump chamber
that houses the driven gear and the drive gear.
Some oil pumps of this kind are disposed on the opposite side of
the input side of the transaxle, that is, on a rear cover side of
the transaxle case. Such an oil pump for a vehicle includes, for
example, a pump chamber formed between the rear cover and a pump
body secured to the rear cover. Additionally, the oil pump includes
the driven gear and the drive gear that engages the driven gear.
The pump chamber houses the driven gear and the drive gear.
The above-described oil pump for a vehicle has a two-layer
structure that includes the rear cover and the pump body. Between
the rear cover of the transaxle case and the pump body, the pump
chamber is formed. This limits flexibility in disposing an oil
passage between the rear cover and the pump body. Accordingly, it
may require providing an independent oil passage (that is, an
additional oil passage) with the rear cover or the pump body. If
the independent oil passage is provided with the rear cover or the
pump body, for example, the rear cover or the pump body may
increase in production cost.
SUMMARY OF THE INVENTION
The present invention provides an oil pump for a vehicle and a
vehicle with the oil pump.
An oil pump for a vehicle according to a first aspect of the
present invention includes a driven gear, a drive gear, a pump
body, and a plate. The drive gear engages the driven gear. The pump
body is secured to a rear cover of a transaxle case. The plate is
interposed between the rear cover and the pump body. A pump chamber
is formed between the rear cover and the pump body. The driven gear
and the drive gear are housed in the pump chamber. The pump chamber
is formed: between the plate and the pump body, or between the
plate and the rear cover.
With the oil pump according to the first aspect of the present
invention, the plate is interposed between the rear cover and the
pump body. Accordingly, the pump chamber is formed between the
plate and the pump body, or between the plate and the rear cover.
In view of this, an oil passage may be formed between the plate and
the rear cover, or between the plate and the pump body. This
eliminates the need for forming an independent oil passage to the
rear cover or the pump body.
Here, in the first aspect of the present invention, the plate may
be made of metal with a higher strength than strengths of the rear
cover and the pump body. The rear cover and the pump body may be
made of light metal. Additionally, the plate may be made of a steel
plate. This configuration reduces the weights of the pump body and
the rear cover. The deformation of the pump chamber is restricted
by the plate. The drive gear and the driven gear have side surfaces
that are in sliding contact with the plate made of a steel plate,
thus increasing a durability of the oil pump.
In the first aspect of the present invention, the rear cover may be
supported by a mounting unit in a vehicle body. This configuration
allows the plate to restrict deformation of the pump chamber due to
a load input from the mounting unit.
In the first aspect of the present invention, the transaxle case
may house an electric motor. Additionally, the pump body may
rotatably support a rotor of the electric motor via a bearing. This
configuration allows the plate to appropriately restrict a
deformation of the pump chamber due to a load input from the
bearing.
In the first aspect of the present invention, the oil pump may
further include a control valve. The control valve includes a valve
element, a valve chamber, and a spring housed in the valve chamber.
The spring biases the valve element in a valve closing direction.
The valve chamber is formed between the plate and the pump body,
and houses the valve element. The plate may include a through hole
that is closed by seating of the valve element. Additionally, when
the control valve opens, an oil passage formed in the rear cover
may be communicated with an oil passage formed in the pump
body.
In the first aspect of the present invention, the plate may include
a plurality of through holes. A plurality of control valves may be
provided at one side of the plate. Additionally, the plurality of
control valves may be disposed corresponding to the plurality of
through holes, and have mutually different valve characteristics.
In this configuration, the plurality of control valves is disposed
parallel to one another at one side of the plate. This
appropriately decreases a dimension of the plate of the pump body
in a thickness direction, thus allowing downsizing of the pump
body.
In the first aspect of the present invention, respective valve
elements of the plurality of control valves may be made of a same
component. Respective springs of the plurality of control valves
may be made of a same component. Additionally, the plurality of
through holes may have mutually different diameters. This
configuration can reduce types of the plurality of valve elements
and springs, thus ensuring the control valve at comparatively low
production costs. This also reduces the possibility to mismount the
valve elements and the springs when mounting the valve elements and
the springs on the valve body.
In the first aspect of the present invention, the plate, the
control valve, and the pump cover may constitute a unit of module.
The unit of module may be mounted on the rear cover. This ensures
quality assurance in a small unit (oil pump sub-assembly). This
allows mechanically checking valve actuation in the sub-assembly,
thus eliminating the need for checking actuation using hydraulic
pressure and air pressure.
A vehicle according to a second aspect of the present invention
includes a rear cover of a transaxle case and an oil pump. The oil
pump includes a driven gear, a drive gear, a pump body, and a
plate. The drive gear engages the driven gear. The pump body is
secured to the rear cover. A pump chamber is formed between the
rear cover and the pump body. The driven gear and the drive gear
are housed in the pump chamber. The plate is interposed between the
rear cover and the pump body. The pump chamber is formed between
the plate and the pump body, or between the plate and the rear
cover.
BRIEF DESCRIPTION OF THE DRAWINGS
The features, advantages, and technical and industrial significance
of this invention will be described in the following detailed
description of example embodiments of the invention with reference
to the accompanying drawings, in which like numerals denote like
elements, and wherein:
FIG. 1 is a diagram illustrating a schematic configuration of a
hybrid vehicle that includes an oil pump for vehicle according to
an embodiment of the present invention;
FIG. 2 is a cross-sectional view illustrating a configuration of
the oil pump for vehicle in FIG. 1;
FIG. 3 is an enlarged view of FIG. 2 illustrating a pump chamber in
the oil pump for vehicle in FIG. 2; and
FIG. 4 is a diagram illustrating a mounting unit mounted on the
rear cover in FIG. 2.
DETAILED DESCRIPTION OF EMBODIMENTS
A description will be given of an embodiment of the present
invention in detail below by referring to the accompanying
drawings. In the following embodiment, the drawings are simplified
or modified as needed for ease of understanding. A dimensional
ratio, a shape, and a similar parameter of each part depicted in
the drawings are not necessarily accurate.
FIG. 1 is a diagram illustrating a schematic configuration of a
hybrid vehicle 12 (hereinafter referred to as a vehicle 12)
including an oil pump 10 for a vehicle according to an embodiment
of the present invention.
In FIG. 1, the vehicle 12 includes a transmission part 22. The
transmission part 22 includes a power distribution mechanism 18 (a
differential mechanism), a gear mechanism 20, and a second electric
motor (an electric motor) MG2. The power distribution mechanism 18
distributes power, which is output from an engine 14 as a driving
force source for running, to a first electric motor MG1 and an
output gear 16. The output gear 16 functions as an output rotation
member of the transmission part 22 (the power distribution
mechanism 18). The gear mechanism 20 is coupled to the output gear
16. The second electric motor MG2 is coupled to the output gear 16
via the gear mechanism 20 so as to allow transmitting the
power.
The above-described transmission part 22 is used for, for example,
an FF (front-engine, front-wheel drive) vehicle where the engine 14
is transversely mounted in the vehicle 12. A power transmission
unit 38 includes a pair of counter gears (14, 26), a pair of final
gears (26, 28), a differential gear unit (a final reduction gear)
30, a damper 32, an input shaft 34, and a similar component. The
pair of counter gears includes the output gear 16 and a counter
driven gear 24. The pair of final gears includes a final drive gear
26 and a final driven gear 28. The damper 32 is operatively coupled
to the engine 14. The input shaft 34 is operatively coupled to the
damper 32. The power transmission unit 38 serves as a transaxle
(T/A) in a transaxle case 36. The transaxle case 36 is mounted on a
vehicle body frame 80 (a vehicle body) illustrated in FIG. 4, which
is described below, and serves as a non-rotating member. The power
transmission unit 38 thus configured transmits a power from the
engine 14 and a power from a second electric motor MG2 to the
output gear 16. Here, the power from the engine 14 is input to the
power transmission unit 38 through the damper 32 and the input
shaft 34. Subsequently, the power from the engine 14 and the power
from the second electric motor MG2 are transmitted from the output
gear 16 to a pair of driving wheels 42 sequentially via the pair of
counter gears and the pair of final gears, a differential gear unit
30, a pair of wheel axes 40, and a similar component.
As illustrated in FIG. 1, the transaxle case 36 includes the second
electric motor MG2, the power distribution mechanism 18, a
transaxle rear cover 44 (hereinafter referred to as a rear cover
44), a cylindrical first case 46, and a cylindrical second case 48.
The rear cover 44 and the first case 46 house the gear mechanism
20. The second case 48 is coupled to a part at the side of the
engine 14 of the first case 46. The second case 48 houses the first
electric motor MG1 and a differential gear unit 30. As illustrated
in FIG. 1, the transaxle case 36 includes the rear cover 44, the
first case 46, and the second case 48 that are integrally secured
using a fastening member 50 such as a bolt.
As illustrated in FIG. 1, the input shaft 34 includes one end part
that is coupled to a crankshaft 52 of the engine 14 via the damper
32. This allows the engine 14 to rotate and drive the input shaft
34. The oil pump 10 is coupled to the other end part of the input
shaft 34. The engine 14 rotates and drives the input shaft 34, thus
driving the oil pump 10.
As illustrated in FIG. 2 and FIG. 3, the oil pump 10 includes a
circular driven gear 54 and a drive gear 56. The drive gear 56
includes external teeth that engage the internal teeth of the
driven gear 54. That is, the oil pump 10 is an internal gear pump
where the driven gear 54 engages the drive gear 56. Here, the other
end part of the input shaft 34 is coupled to the drive gear 56 such
that the input shaft 34 is unrotatable with respect to the drive
gear 56.
As illustrated in FIG. 2 and FIG. 3, the oil pump 10 includes a
pump body 58, a flat plate 60, and a pump chamber 62. The pump body
58 is secured to the rear cover 44. The plate 60 is interposed
between the pump body 58 and the rear cover 44. The pump chamber 62
is formed between the plate 60 and the pump body 58. The pump
chamber 62 has a columnar space surrounded by an inner peripheral
surface 58b, a first inner wall surface 58c, and a second inner
wall surface 60a. That is, the columnar space is a space surrounded
by a dashed line illustrated in FIG. 3. The inner peripheral
surface 58b is formed by depressing an end surface 58a of the pump
body 58 at the plate 60 side in a columnar shape. The first inner
wall surface 58c is positioned at one end part of the inner
peripheral surface 58b in the shaft center direction of the input
shaft 34. The second inner wall surface 60a is positioned at the
other end part of the inner peripheral surface 58b in the shaft
center direction of the input shaft 34. The pump chamber 62
rotatably houses the driven gear 54 and the drive gear 56.
As illustrated in FIG. 2 and FIG. 3, the oil pump 10 includes an
oil passage 64 constituted by a groove 44a of the rear cover 44 and
the plate 60. Hydraulic oil that is discharged from the oil pump 10
is supplied to the oil passage 64. Then, the hydraulic oil is
supplied from the oil passage 64 to a hydraulic pressure control
circuit.
As illustrated in FIG. 2, the plate 60 is secured to the pump body
58 and the rear cover 44 using a first fastening bolt 66 and a
second fastening bolt 68 such as a bolt. As described above, the
plate 60 is interposed between the pump body 58 and the rear cover
44. The rear cover 44 and the pump body 58 are made of light metal,
for example, aluminum alloy. The plate 60 is made of a metal plate
with a higher strength than strengths of the rear cover 44 and the
pump body 58, for example, made of a steel plate.
As illustrated in FIG. 2 and FIG. 3, the pump body 58 includes a
cylindrical protrusion 58d. The protrusion 58d protrudes in the
axis direction from the end part of the pump body 58 at the side of
the second electric motor MG2 toward the second electric motor MG2.
A bearing 72 is interposed between the protrusion 58d and a rotor
70 in the second electric motor MG2. This allows the protrusion 58d
on the pump body 58 to rotatably support the rotor 70 in the second
electric motor MG2 via the bearing 72.
As illustrated in FIG. 2, the pump body 58 in the oil pump 10
includes a pair of control valves 74 and 76 inside. In this
embodiment, the oil pump may include a plurality of the control
valves at a surrounding of the input shaft 34. The control valves
74 and 76 each include a valve chamber 58e, a valve element 58f,
and a spring 58g. The valve chamber 58e is formed between the pump
body 58 and the plate 60. The valve element 58f is housed in the
valve chamber 58e such that the valve element 58f is movable in the
thickness direction of the plate 60. The spring 58g is housed in
the valve chamber 58e, and biases the valve elements 58f in the
valve closing direction. The pair of control valves 74 and 76
serves as, for example, a relief valve. The pair of control valves
74 and 76 drain hydraulic oil in the oil passage 64, which is
formed in the rear cover 44, to a return oil passage (not shown)
formed in the pump body 58. The pair of control valves 74 and 76
include the valve elements 58f and the springs 58g that are each
the same component. That is, the respective valve elements 58f of
the plurality of control valves 74 and 76 are made of a same
component, and the respective springs 58g of the plurality of
control valves 74 and 76 are made of a same component.
As illustrated in FIG. 2, the plate 60 includes a pair of through
holes 60b and 60c. The through holes 60b and 60c have a circular
shape and communicate the valve chambers 58e in the pair of control
valves 74 and 76 with a space in the oil passage 64. It is
configured that the valve elements 58f in the pair of control
valves 74 and 76 are seated on the plate 60 by biasing force of the
springs 58g so as to close the pair of respective through holes 60b
and 60c. As illustrated in FIG. 2, the pair of control valves 74
and 76 is disposed at the side of the pump body 58 on the plate 60.
The pair of control valves 74 and 76 corresponds to the pair of
respective through holes 60b and 60c. That is, the pair of control
valves 74 and 76 is disposed in parallel in the pump body 58.
As illustrated in FIG. 2, the through holes 60b and 60c, which are
formed on the plate 60, have mutually different diameters R1 and
R2. The pair of control valves 74 and 76 has a valve characteristic
where the valve elements 58f of the control valves 74 and 76 open
when hydraulic pressure of the hydraulic oil in the oil passage 64
is a valve opening set pressure. As described above, the pair of
the control valves 74 and 76 has the valve elements 58f and the
springs 58g that employ the same component. Accordingly, the valve
characteristic varies depending on the size of the diameters R1 and
R2 of the through holes 60b and 60c on the plate 60. In view of
this, the control valves 74 and 76 have mutually different valve
opening characteristics.
As illustrated in FIG. 2, the plate 60, the pair of control valves
74 and 76, and the pump body 58 is preliminarily assembled using
the first fastening bolt 66 and constitute a module as one unit.
Accordingly, the plate 60, the pair of control valves 74 and 76,
and the pump body 58 is mounted as a module on the rear cover 44
using the second fastening bolt 68. That is, the module constituted
of the plate 60, the pair of control valves 74 and 76, and the pump
body 58 is mounted on the rear cover 44.
FIG. 4 is a diagram illustrating a mounting unit 78 mounted on the
rear cover 44 of the transaxle case 36. According to FIG. 4, the
rear cover 44 is supported by the mounting unit 78 provided with a
side member 80a. The side member 80a is disposed at the left side
of a vehicle body frame 80 in a vehicle front direction illustrated
in FIG. 4. In FIG. 4, an arrow FR indicates the vehicle front
direction.
As illustrated in FIG. 4, the mounting unit 78 includes a vehicle
body frame side member 82, a transaxle side member 84, and a
cylindrical mount bush (not shown). The vehicle body frame side
member 82 is integrally fastened to the side member 80a using a
plurality of bolts. The transaxle side member 84 is fastened to the
rear cover 44 using a plurality of bolts. The mount bush is made of
an elastic member such as a rubber that is interposed between the
transaxle side member 84 and the vehicle body frame side member 82.
The mount bush absorbs or damps vibration that occurs in the power
transmission unit 38 or the transaxle.
According to the oil pump 10 in this embodiment, the plate 60 is
interposed between the rear cover 44 and the pump body 58. The pump
chamber 62 is formed between the plate 60 and the pump body 58.
This allows forming the oil passage 64 between the plate 60 and the
rear cover 44. In this configuration, it is not necessary to form
an independent oil passage to the rear cover 44 or the pump body
58.
According to the oil pump 10 in this embodiment, the rear cover 44
and the pump body 58 are made of aluminum alloy. The plate 60 is
made of a steel plate with a higher strength than strengths of the
rear cover 44 and the pump body 58. While reducing the weights of
the pump body 58 and the rear cover 44, the deformation of the pump
chamber 62 is restricted by the plate 60 with the high strength.
The drive gear 56 and the driven gear 54 have side surfaces that
are in sliding contact with the plate 60 made of a steel plate,
thus increasing durability of the oil pump 10.
According to the oil pump 10 in this embodiment, the rear cover 44
is supported by the mounting unit 78 disposed in the side member
80a of the vehicle body frame 80. Thus, a deformation of the pump
chamber 62 caused by a load input from the mounting unit 78, that
is, a deformation of the rear cover 44 is restricted by the plate
60 with the high strength. Especially, this effect is significant
because the plate 60 is made of a steel plate.
According to the oil pump 10 in this embodiment, the transaxle case
36 houses the second electric motor MG2 inside. The pump body 58
rotatably supports the rotor 70 in the second electric motor MG2
via the bearing 72. Thus, a deformation of the pump chamber 62
caused by a load input from the bearing 72, that is, a deformation
of the pump body 58 is appropriately restricted by the plate 60
with the high strength. Especially, this effect is significant
because the plate 60 is made of a steel plate.
According to this embodiment, the oil pump 10 includes the valve
elements 58f and the control valves 74 and 76. The valve elements
58f are housed in the valve chambers 58e formed between the plate
60 and the pump body 58. The control valves 74 and 76 include the
springs 58g housed in the valve chambers 58e and bias the valve
elements 58f in the valve closing direction. The plate 60 has the
through holes 60b and 60c, which are closed by seating of the valve
elements 58f in the control valves 74 and 76. The control valves 74
and 76 drain hydraulic oil in the oil passage 64, which is formed
in the rear cover 44, to the oil passage, which is formed in the
pump body 58. That is, in the case where the control valves 74 and
76 open, the oil passage 64 formed in the rear cover 44 is
communicated with the oil passage formed in the pump body 58. In
this configuration, the valve elements 58f of the control valves 74
and 76 seal the through holes 60b and 60c at valve sealing surfaces
of the plate 60. The valve sealing surfaces are made of a steel
plate. This appropriately prevents abrasion of the peripheral parts
of the through holes 60b and 60c on the plate 60.
According to the oil pump 10 in this embodiment, the plate 60 has
the pair of through holes 60b and 60c. The pair of control valves
74 and 76 is disposed on a surface at one side of the plate 60
corresponding to the pair of respective through holes 60b and 60c.
The control valves 74 and 76 have mutually different valve
characteristics. In view of this, control valves 74 and 76 are
disposed parallel to one another at one side surface of the plate
60. This decreases a dimension of the plate 60 of the pump body 58
in a thickness direction, thus allowing downsizing of the pump body
58. Note that, in this embodiment, the plate 60 may include a
plurality of the through holes corresponding to the respective the
plurality of the control valves.
According to the oil pump 10 in this embodiment, the valve elements
58f of the pair of control valves 74 and 76 are each made of a same
component, and furthermore the springs 58g of the pair of control
valves 74 and 76 are each made of a same component. The through
holes 60b and 60c, which are closed by the valve elements 58f of
the pair of control valves 74 and 76, have mutually different
diameters R1 and R2. This reduces types of the valve elements 58f
and springs 58g in the pair of control valves 74 and 76, thus
ensuring the pair of control valves 74 and 76 at comparatively low
production cost. This also prevents mismounting of the valve
elements 58f and the springs 58g when mounting the valve elements
58f and the springs 58g on the pump body 58.
According to the oil pump 10 in this embodiment, the plate 60, the
pair of control valves 74 and 76, and the pump body 58 constitute a
module assembled as one unit. Accordingly, the plate 60, the pair
of control valves 74 and 76, and the pump body 58 are mounted as a
module on the rear cover 44. This ensures quality assurance in a
small unit (oil pump sub-assembly). This allows mechanically
checking valve actuation in the sub-assembly. In this
configuration, it is not necessary to check actuation using
hydraulic pressure and air pressure.
While one embodiment according to the present invention is
described above based on the drawings, the present invention is
also applied to other aspects.
For example, in the oil pump 10 in this embodiment, the pump
chamber 62 is formed between the plate 60 and the pump body 58, and
the oil passage 64 is formed between the plate 60 and the rear
cover 44. In contrast, for example, the pump chamber 62 may be
formed between the plate 60 and the rear cover 44, and the oil
passage 64 may be formed between the plate 60 and the pump body
58.
The oil pump 10 according to the embodiment is an internal gear
pump where the circular driven gear 54 engages the drive gear 56.
The drive gear 56 has the external teeth that engage the internal
teeth of the driven gear 54. In contrast, for example, the oil pump
may be an external gear pump where external teeth of a drive gear
engage external teeth of a driven gear.
While in the oil pump 10 of this embodiment, the rear cover 44 and
the pump body 58 are made of aluminum alloy, a light metal other
than aluminum alloy may be employed. Additionally, while the plate
60 is made of a steel plate, any metal plate may be used insofar as
the metal plate has a higher strength than the strengths of the
rear cover 44 and the pump body 58.
Obviously, numerous modifications and variations of the present
invention are possible in light of the above teachings. It is to be
understood that the present invention may be embodied with various
other changes, modifications and improvements, which may occur to
those skilled in the art.
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